The use of electrical connector assemblies for the purpose of electrically coupling various circuit devices is, of course, well known, with several examples being shown and described in the following patents and publications, the disclosures of which are incorporated herein by reference:
U.S. Patents:
U.S. Pat. No. 3,861,135--R. E. Seeger, Jr. et al PA0 U.S. Pat. No. 3,883,213--F. J. Glaister PA0 U.S. Pat. No. 3,971,610--L. S. Buchoff et al PA0 U.S. Pat. No. 4,184,729--H. L. Parks et al PA0 U.S. Pat. No. 4,575,166--D. G. Kasdagly et al PA0 U.S. Pat. No. 4,577,918--D. G. Kasdagly PA0 U.S. Pat. No. 4,902,234--W. L. Brodsky et al PA0 U.S. Pat. No. 4,927,368--K. Shino PA0 U.S. Pat. No. 5,033,675--K. Shino PA0 U.S. Pat. No. 5,059,129--W. L. Brodsky et al PA0 U.S. Pat. No. 5,099,393--J. R. Bentlage, et al PA0 U.S. Pat. No. 5,142,449--H. W. Littlebury et al PA0 U.S. Pat. No. 5,163,834--F. W. Chapin et al PA0 U.S. Pat. No. 5,338,208--A. Bross et al PA0 Vol. 12, No. 12(5/70) p. 2313 PA0 Vol. 18, No. 2(7/75) p. 340 PA0 Vol. 22, No. 2(7/79) pp. 444-445 PA0 Vol. 25, No. 7A(12/82) pp. 3438-3441
IBM Technical Disclosure Bulletins:
Electrical connector assemblies wherein direct contact is desired between the individual electrical conductors (e.g., printed circuit lines, contact pins, etc.) which constitute part of the circuit devices being coupled, as in the case of the instant invention, mandate the application of a reliable contact pressure of sufficient duration and capable of withstanding possible adverse environmental conditions (e.g., heat, moisture). Excessive pressure can result in damage to various components of the assembly (particularly the conductors) during both assembly and/or operation. Additionally, the provision of such pressure has heretofore often been accomplished through the utilization of relatively large components (e.g., connector housings) needed to produce these assemblies, thus also adding unnecessarily to the cost thereof In those assemblies subjected to adverse environmental conditions, failure to withstand same has resulted in such problems as contact corrosion, reduced contact pressure, increased maintenance costs, etc.
U.S. Pat. No. 4,902,234, assigned to the same assignee as the instant invention, defines a connector assembly wherein an elastomeric pressure exertion member is utilized to provide reliable contact pressure against at least one of the circuit members (e.g., a flexible circuit). This exertion member includes a base plate, a plurality of individual compressible elements located on one side of the plate, and a resilient member located on the plate's other side.
U.S. Pat. Nos. 5,059,129 and 5,099,393, both also assigned to the same assignee as the present invention, define electrical connector assemblies for coupling various circuitized substrates such as printed circuit boards wherein elastomeric pressure exertion members are utilized. In both, a stepped, two-layered elastomeric is defined wherein the base (or first) layer includes spaced apertures therein and the upper (or second) layer includes several upstanding projections all of which are strategically located in a specific pattern such that each is oriented adjacent one or more respective apertures. See, e.g., FIG. 6, in U.S. Pat. No. 5,059,129 and FIGS. 10 and 11 in U.S. Pat. No. 5,099,393. The working relationship between such projections, base layer apertures and the respective substrates being engaged to effect electrical coupling is seen in the earlier figures in these patents (e.g., FIG. 3 in U.S. Pat. No. 5,059,129). Significantly, the dual layered (called bilayered in these two patents) elastomeric members in U.S. Pat. Nos. 4,902,234, 5,059,129 and 5,099,393 are typically shown and described as being of one integral unit of the same elastomeric material throughout. (See e.g., col. 7, lines 2-6 of U.S. Pat. No. 4,902,234, col. 5, lines 60-63 of U.S. Pat. No. 5,059,129, and col. 8, lines 43-46 of U.S. Pat. No. 5,099,393). U.S. Pat. Nos. 4,902,234, 5,059,129 and 5,099,393 are incorporated herein by reference.
The formation of elastomeric members as taught in the immediately foregoing two patents, while producing very acceptable exertion force structures, often requires the utilization of relatively complicated mold assemblies to assure proper aperture location in the base layers and precise adjacent placement of the respective upstanding projections for the resulting integral structure. A relatively complicated mold assembly is also understandably needed to produce the elastomeric-metal plate structure defined in U.S. Pat. No. 4,902,234.
It is believed that an electrical connector assembly embodying a pressure exertion member which is comprised of two individual layers each of a different hardness material and which can be manufactured using relatively less complicated mold apparatus and procedures than those known before (particularly in the three patents cited immediately above) would constitute a significant advancement in the art.